Teratology of thioxanthone derivatives: The contractor shall initially determine what effects, at what dose range, during which period of organogenesis, analog of a thianthone derivative may have on the dam and developing mouse embryo. Six analogs will be studied. Mice will be sacrificed on day 17 or gestation. Professional interpretation as to general condition of the dam as well as pattern of lethal and toxic fetal effecits is to be made at time of sacrifice. Fetus be examined.